1. Field of the invention.
This invention relates to radiation detection and imaging devices and methods for locating each of a plurality of photon emitting sources, and more particularly to instrumentation for surveying the disposition of a distributed radiation source such as a radioactive pharmaceutical in the human body and displaying a more accurate image of said distribution.
2. Description of the prior art.
Tobias U.S. Pat. No. 2,779,876 provides photodetectors disposed adjacent a scintillator for locating the image point in the scintillator after photon emission by determining which phototube provides a responsive signal. Anger U.S. Pat. No. 3,011,057 improved resolution to an area smaller than a phototube by spacing the phototubes a moderate distance from the scintillator so that several phototubes may report each light flash. The electrical signals from the phototubes are combined in a coordinate system relative to their positions over the scintillator and report the approximate location of the scintillation in the crystal but not the location of the radiation source. Blum U.S. Pat. No. 3,878,373 provides locating of the radiation source in the image by comparing the phototube signal pattern caused by the scintillation from the source in unknown location with signal patterns generated when sources are in known locations.